Electric incandescent lamp with tapered sealing collar

ABSTRACT

An electric incandescent lamp with its lead-in wires formed with an integral collar the periphery of which forms a hermetic seal with the lamp envelope. The method of manufacturing the lamp using this lead-in wire whereby the exhausting and filling operations are performed through one end of the envelope.

United States Patent Ayres [54] ELECTRIC INCANDESCENT LAMP WITH TAPERED SEALING COLLAR [72] Inventor: Reginald J. Ayres, Cape Coral, Fla.

[73] Assignee: General Electric Company [22] Filed: May 26, 1970 [21] Appl. No.: 40,508

[ 1 Feb. 29, 1972 2,148,315 2/1939 Wright ..313/271 X 1,983,679 12/1934 Scofield..... ...313/274 X 3,040,204 6/1962 Belknap.... ....313/274 X 2,191,346 2/1940 Greiner ..313/274 Primary ExaminerDavid Schonberg Assistant Examiner-Toby H. Kusmer Attorney-Henry P. Truesdell, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman [57] ABSTRACT An electric incandescent lamp with its lead-in wires fonned with an integral collar the periphery of which forms a hermetic seal with the lamp envelope. The method of manufacturing the lamp using this lead-in wire whereby the exhausting and filling operations are performed through one end of the envelope.

5 Claims, 5 Drawing Figures PATENTEBFEB29I972 3,646,387

Fig 1. -Fig; Z.

" VFICUUM lnven tor: g hd d. Agrees y MW mac. His A t torneg ELECTRIC INCANDESCENT LAMP WITH TAPERED SEALING COLLAR BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to electric incandescent lamps comprised of a sealed envelope, lead-in wires and an incandescible filament. More particularly, the invention relates to the lead-in wires which form a hermetic seal with the envelope and the method of manufacturing a lamp using the lead-in wires of the invention.

2. Description of the Prior Art In the past, lead-in wires have been sealed to lamp envelopes in a variety of ways. One of these variations is where glass beads are fused to the lead-in wires and the glass beads in turn fuse with the glass envelope during the sealing operation. Another method of making seals is by attaching thin molybdenum foils to the outer lead wire. The glass wets and adheres to the thin foil thereby forming the seal. Each of these methods present problems of volume control within the envelope. The methods of the prior art are also more expensive in that they necessitate the use of additional material such as an exhaust tube and require additional manufacturing processing such as the exhaust tube tipping operation.

Another form of seal is one using thimbles which are fused to the envelope as for example, in US. Pat. No. 2,191,346 to Greiner, assigned to the same assignee as the present invention. The use of the thimble-type construction requires the delicate location and melting of the fusible material to seal the envelope.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is an elevation view of the lead-in wire for an electric lamp according to the invention;

FIG. 2 is an elevation of a mount assembly for an electric lamp according to the invention;

FIG. 3 is a view illustrating one of the steps in the method of making an electric lamp according to the invention;

FIG. 4 is a view illustrating a further step in the manufac ture; and

FIG. 5 shows a finished lamp embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the lamp of the invention comprises a lead-in wire or rod 10, which may be of platinum, and which is mechanically upset or swaged adjacent one end to form a collar or flange 11 of general circular configuration and of somewhat larger diameter than the lead-in wire. The collar is preferably spaced somewhat from the end of the lead-in wire to provide a spud 12 for attachment of a filament, the collar being tapered at its periphery as indicated at 13 to facilitate sealing thereof to a lamp envelope. As shown in FIG. 2, opposite ends of an incandescible filament 14 are spot welded or otherwise suitably fastened, as shown at 15, to the spuds 12 of the lead-in wires 10. The lamp components thus assembled constitute a lamp mount structure designed for mounting as a unit in a lamp envelope.

In FIG. 3, the mount structure comprised of the assembled lead-in wires and filament 14 is shown placed within an elongated tubular envelope 16 of vitreous material such as glass. Following the insertion of the mount structure into the envelope, the entire assembly of lead-in wires, filament and envelope is positioned in a sealing and exhaust head 17 such that the envelope 16 is in a sealing relationship with respect to the collars 11 of the lead-in wires 10. Scaling and exhaust head 17 is comprised of a housing 18, a compression rubber chuck 19, a lead-in wire holder 20, a locking ring 21, and a gas-filling and exhaust passageway 22 in the housing 18.

As can be seen from FIG. 3, the bottom portion of the glass envelope 16 is inserted into the compression rubber chuck 19 which includes a rubber ring 23 with an opening 24 therein and a top cap 25 threaded into the housing 18 as shown at 26. In assembled position, the rubber ring 23 is compressed to hold envelope l6 securely in position and form an airtight seal between the rubber ring and the envelope.

FIG. 3 also illustrates the lead-in wire holder 20 which in cludes a mount pin portion 28 having an axial bore 29, a flange section 30 and an opening 31. The lead-in wire holder 20 is held in place within the housing 18 by the locking ring 21 which screw threads into the passageway 22 in the housing to clamp the flange 30 of the lead wire holder against the annular shoulder 27 of the housing. Lead-in wire 10 is held within the axial bore 29, and the mount pin portion projects upwardly into the lower end of the envelope to center and firmly support the mount structure within the envelope 16. The mount pin portion 28 of the lead-in wire holder can be of a split sleeve construction so as to exert a gripping force on the lead wire and hold it firmly in place. Both the locking ring 21 and the lead-in wire holder 20 have openings therein to provide a continuation of passageway 22 for the flow of gas therethrough as indicated by the arrows in FIG. 3.

The upper lead-in wire 10 is held in place by a springoperated clamping jaw 32. Clamping jaw 32 and lead-in wire holder 20 are appropriately spaced so as to hold the filament 14 in tension. Envelope 16 is also securely held in place adjacent its upper end by clamping jaw means 33.

Once the lead-in wires 10 and the envelope 16 are assembled in sealing positions, heat is applied as illustrated in FIG. 3 to the upper end of the envelope in the area surrounding the collar 11 of the uppermost lead-in wire 10 by means of sealing fires 34 projecting from burners 35 so that the envelope glass softens and'flows onto the collar portion 11 of the lead-in wire and through its adherence to the metal collar forms a hermetic seal with the tapered portion 13. Prior to the application of the heat to the envelope 16, a nonoxidizing gas is flowed through the filling and exhaust passageway 22 of the housing 18 and into the envelope by opening one part of the two-way valved conduit 36'which is connected to a gas supply. The gas flows around the lead-in wires 10 and filament 14 so as to prevent oxidation of these parts during the heating of the upper part of the envelope.

After the upper end of the envelope has been sealed to the upper lead-in wire 10 as described above, the valve 36 is turned to the off position. A vacuum is then created in the envelope by opening the valve 37 which is connected to a vacuum supply. After the passageway 22 and envelope 16 have been completely evacuated, the vacuum valve 37 is turned off. At this point in the manufacturing process, an inert gas such as nitrogen or argon may be introduced, if desired, into the envelope by opening the inert gas portion of the twoway valved conduit 36 subsequent to the closing of the vacuum valve 37.

Once the envelope 16 is filled with the inert gas or the vacuum condition is created therein, heat is then applied to the lower end portion of the envelope surrounding the collar 11 on the lower lead-in wire 10 by means of sealing fires 38 from burners 39, as is illustrated in FIG. 4. The glass of the lower portion of the envelope then softens and flows onto the collar portion of the lead-in wire and adheres thereto and the lower end of the envelope fired off as scrap.

The finished lamp shown in FIG. 5 is thus easily made with a minimum number of parts and manufacturing operations. By using the lead-in wire with the integral collar certain lead manufacturing processes are eliminated for example the attaching of the outer lead wire to foils or the fusing of glass beads to lead wires. The flange or collar lead wire construction also reduces the overall length of the lamp in that the thickness of the collar which forms the seal is smaller than the corresponding dimensions of the foil or head or thimble. Accuracy in bulb volume is achieved because the lead-in wires are manufactured by a metal working process which has greater precision than the glass working or metal assembly processes of the prior art. Furthermore, the number of lamp components is reduced by eliminating the exhaust tube in that the exhausting operation can be performed through one end of the envelope. Manufacture is simplified in that the fires alone cause the glass to flow and form the seal without'the aid of the mechanical action of the usual pinch jaws for making the pinch seal around the lead wires.

it will further be evident that various modifications, changes and omissions may be made in details of the construction illustrated herein without departing from the spirit and scope of the invention as set forth in the appended claims.

What i claim as new and desire to secure by Letters Patent of the United States is:

1. An electric incandescent lamp comprising a glass envelope, a filament disposed in said envelope, and a pair of lead-in wires of a material having a coefficient of expansion approximately matching that of the glass of said envelope,

wherein the improvement is comprised of said lead-in wires each having an integral sealing flange thereon and being hermetically sealed into said envelope by fused seals of the glass envelope to the peripheral region of the said sealing flanges said peripheral region being tapered to facilitate the formation of said fused seals.

2. An electric lamp as specified in claim 1 wherein the said sealing flange on each of said lead-in wires is constituted by an upset collar thereon.

3. An electric lamp as specified in claim 1 wherein the said sealing flange on each lead-in wire is located intermediate the ends thereof.

4. An electric lamp as specified in claim 1 wherein the said envelope is constituted of a soft glass and the said lead-in wires are constituted of platinum.

S. An electric lamp comprising a tubular glass envelope, a filament disposed in said envelope and a pair of lead-in wires sealed into opposite ends of said envelope and constituted of a material having a coefficient of expansion approximately matching that of the glass of said envelope, said lead-in wires each having an integral sealing flange thereon and being hermetically sealed into the opposite ends of said envelope by fused seals of the glass envelope to the peripheral regions of the said sealing flanges said peripheral regions being tapered to facilitate the formation of said fused seals. 

1. An electric incandescent lamp comprising a glass envelope, a filament disposed in said envelope, and a pair of lead-in wires of a material having a coefficient of expansion approximately matching that of the glass of said envelope, wherein the improvement is comprised of said lead-in wires each having an integral sealing flange thereon and being hermetically sealed into said envelope by fused seals of the glass envelope to the peripheral region of the said sealing flanges said peripheral region being tapered to facilitate the formation of said fused seals.
 2. An electric lamp as specified in claim 1 wherein the said sealing flange on each of said lead-in wires is constituted by an upset collar thereon.
 3. An electric lamp as specified in claim 1 wherein the said sealing flange on each lead-in wire is located intermediate the ends thereof.
 4. An electric lamp as specified in claim 1 wherein the said envelope is constituted of a soft glass and the said lead-in wires are constituted of platinum.
 5. An electric lamp comprising a tubular glass envelope, a filament disposed in said envelope and a pair of lead-in wires sealed into opposite ends of said envelope and constituted of a material having a coefficient of expansion approximately matching that of the glass of said envelope, said lead-in wires each having an integral sealing flange thereon and being hermetically sealed into the opposite ends of said envelope by fused seals of the glass envelope to the peripheral regions of the said sealing flanges said peripheral regions being tapered to facilitate the formation of said fused seals. 